Ge1−xSnx/Ge heterostructure infrared photodetector

We report the optoelectronic characterization of Ge_2-xSn_x/Ge heteroj unction infrared (IR) photodetectors fabrication on Si substrate using rapid thermal chemical vapor deposition (RTCVD) with Ge₂H₆ and SnCl₄ precursors and in a CMOS compatible process. We obtained that Sn contents in Ge_1-xSn_x. epitaxial layer ~5.9%. The surface roughness root mean square (RMS) were 1.2 nm. The leakage current of a device as low as 0.7 μA at 1 V and leakage current reduced as device size decrease. At 1550 nm wavelength, the responsivity of the Ge_1-xSn_x/Ge devices was estimated to be 54 mA/W was measured for a bias of 2 V, without an optimal antireflection coating. Fabricated device shows practicability for optoelectronic applications in the extended IR wavelength regime.